title: Multifunctional silk-heparin biomaterials for vascular tissue engineering applications.
abstract: Over the past 30 years, silk has been proposed for numerous biomedical applications that go beyond its traditional use as a suture material. Silk sutures are well tolerated in humans, but the use of silk for vascular engineering applications still requires extensive biocompatibility testing. Some studies have indicated a need to modify silk to yield a hemocompatible surface. This study examined the potential of low molecular weight heparin as a material for refining silk properties by acting as a carrier for vascular endothelial growth factor (VEGF) and improving silk hemocompatibility. Heparinized silk showed a controlled VEGF release over 6 days; the released VEGF was bioactive and supported the growth of human endothelial cells. Silk samples were then assessed using a humanized hemocompatibility system that employs whole blood and endothelial cells. The overall thrombogenic response for silk was very low and similar to the clinical reference material polytetrafluoroethylene. Despite an initial inflammatory response to silk, apparent as complement and leukocyte activation, the endothelium was maintained in a resting, anticoagulant state. The low thrombogenic response and the ability to control VEGF release support the further development of silk for vascular applications.
authors.affiliation: Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, MA 02155, USA.
authors.forename: F Philipp
authors.initials: FP
authors.lastname: Seib
authors.forename: Manuela
authors.initials: M
authors.lastname: Herklotz
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Burke
authors.forename: Manfred F
authors.initials: MF
authors.lastname: Maitz
authors.forename: Carsten
authors.initials: C
authors.lastname: Werner
authors.forename: David L
authors.initials: DL
authors.lastname: Kaplan
mesh_terms: D001672:Biocompatible Materials; D001808:Blood Vessels / Q000166:cytology*; D006493:Heparin; D006801:Humans; D047011:Silk; D023822:Tissue Engineering
chemical_list: D001672:Biocompatible Materials; D047011:Silk; D006493:Heparin
keywords: Blood compatibility; Endothelial cells; Heparin; Silk; VEGF; Vascular engineering